This is the second resubmission of an application for a Mentored Patient-Oriented Research Career Development Award (K23) to support the academic career development of the applicant. The candidate's long term goal is to develop a program of clinically-relevant, translational research focused on examining the influence and modifiability of sleep disturbance in the course and treatment of childhood anxiety disorders. Previously, the applicant has conducted research focused on the development of anxiety disorders in children and adolescents, including the prevalence of sleep disturbance. This application proposes training that is necessary for the next step in this research program, including advanced training in pediatric sleep medicine, laboratory-based training in the use and interpretation of polysomnography, assessment of neurohormonal dimensions of arousal in anxious children, and further training in research ethics and methodology. The mentorship of a select group of senior investigators will foster the candidate's development in a promising new area of research integrating two distinct areas of investigation: sleep medicine and developmental psychopathology. Prior research indicates that more than 90% of children with Generalized Anxiety Disorder (GAD) experience problems initiating and/or maintaining sleep; rates that are similar or higher than those found among adults with the disorder. Because persistent sleep disturbance during childhood is independently associated with multiple impairments in functioning including academic failure, decreased emotion regulation, decrements in attention and reasoning skills, injury risk, and risk-taking behavior, sleep problems among children with GAD may compound existing impairments, exacerbate anxiety symptoms, and result in lower recovery and higher relapse rates. The proposed study will use rigorous methods of assessment to address two primary aims: 1) to evaluate the persistence, features and daytime sequelae of sleep disturbance in children with GAD compared to a group of matched controls based on a one-week prospective, at-home assessment; and 2) to identify specific factors associated with the presence of sleep problems among children with GAD related to neurophysiologic and cognitive dimensions of arousal, and parenting and environmental factors. The training and research outlined in this proposal will equip the candidate with a unique set of necessary skills to advance knowledge in this important and under-researched area. Over the long-term, data will inform the development of empirically-based interventions for children with both sleep and anxiety disorders.